This invention relates generally to mechanisms for changing transfer case speeds in four-wheel drive vehicles. More particularly, the invention relates to the axial translation of a shifter sleeve between high and low speed range positions without requirement of mechanical actuation by a shift fork.
A majority of transfer cases provide a mechanism whereby a vehicle may be converted from a two-wheel to a four-wheel drive mode for purposes of enhancing driveability on off-highway surfaces, as well as on-highway surfaces under inclement conditions. In addition, most transfer cases provide a means for shifting between high and low speed range positions. In such cases, the high range represents a general purpose normal use; the low range is selected for operations in which either more power is required and/or the vehicle is to be operated at slower speeds.
Prior art range speed gears have been shifted between high and low positions by conventional shift forks. Thus, it has been necessary to employ shifter sleeves having mechanical shift forks attached to the sleeves for achieving axial translation of the sleeve between high and low range gear positions.